Fluid-driven medical or dental handle

ABSTRACT

A medical or dental, fluid-driven handle with a control or regulation circuit for the limiting, control or regulation to a maximum or predetermined rotational speed and a corresponding process are presented. The handle comprises a rotary part that can be set in rotary motion by a drive fluid, a fluid line carrying the drive fluid to or from the rotary part or a fluid branch line that is connected to a fluid line carrying drive fluid, and a control or regulation circuit designed to limit, control or regulate the rotational speed of the rotary part. An electrodynamic converter is driven by the rotary part for generating electrical energy and at least one actuator element is configured to act on the drive fluid. The actuator element is electrically connected to the electrodynamic converter such that it is supplied with electrical energy generated by the electrodynamic converter.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority from the pending European PatentApplication No. 10190072.8, filed Nov. 5, 2010, which is incorporatedherein by reference.

BACKGROUND

1. Field

This application relates to a fluid-driven medical or dental handle witha rotary part and a control or regulation circuit for the limiting,control or regulation of the rotational speed of the rotating part, anda process for the limiting, control or regulation of the rotationalspeed of the rotary part.

2. Description of Prior Art

The patent application US 2010/055642 A1, which is commonly owned,discloses a fluid-driven handle with a control or regulation circuit forrotary speed limiting. The handle comprises a rotary part that can beset in rotary motion by a drive fluid to drive a tool that can beconnected to the rotary part, an electrodynamic converter driven by therotary part for the induction of electric voltage and at least oneswitching element for the selectable opening and closing of an electriccircuit between the two ends of a coil of the electrodynamic converter,so that with the electric circuit closed an electric current and aninduction magnetic field braking the rotary speed of the rotary part andthe tool that can be connected to it can be induced.

It would be advantageous to create a fluid-driven medical or dentalhandle with an alternative device for the limiting, controlling orregulation of the rotary speed.

SUMMARY

According to one embodiment, this is achieved by a medical or dental,fluid-driven handle comprising: a rotary part that can be set in rotarymotion by a drive fluid to drive a tool that can be connected to therotary part, a fluid line carrying the drive fluid to or from the rotarypart or a fluid branch line that is connected to a fluid line carryingthe drive fluid to or from the rotary part, and a control or regulationcircuit that is designed to limit, control or regulate the rotationalspeed of the rotary part, wherein the control or regulation circuit hasan electrodynamic converter for the generation of electric energy drivenby the rotary part and at least one actuator element that is configuredto act on the drive fluid flowing in the fluid line or the fluid branchline, wherein the at least one actuator element is electricallyconnected to the electrodynamic converter in such a way that the atleast one actuator element can be supplied with the electric energygenerated by the electrodynamic converter to carry out the actuationprocess.

The control or regulation circuit is thus designed as a control orregulation circuit acting on the drive fluid of the rotary part or as apneumatic control or regulation circuit. The control or regulationcircuit directly changes via the actuator element a parameter of thedrive fluid, for example the fluid pressure or the volume flow, so thatthe rotational speed of the rotary part is limited, controlled,regulated or changed. The electrodynamic converter is thus designed asan energy source for the actuator element or for the actuation of theactuator element. At least a part of the electrical energy generated bythe electrodynamic converter is thus provided or used for the actuationof the actuator element, for example to move a mobile component of theactuator element.

Preferably the at least one actuator element is also electricallyconnected to the electrodynamic converter in such a way that the effectof the actuator element on the drive fluid takes place depending on therotational speed of the rotary part. The electrical energy generated bythe electrodynamic converter is thus used for two purposes: first, itserves to cause the actuator element to act on the drive fluid or tocarry out an actuation process acting on the drive fluid on the part ofthe actuator element, thus it is required by the actuator element forthat element to carry out an actuation movement; and second, due to theparticularly positive correlation between the electrical energygenerated by the electrodynamic converter and the rotational speed ofthe rotary part (as the rotational speed increases the electrical energygenerated increases and/or as the rotational speed decreases theelectrical energy generated decreases), the rotational speed of therotary part is determinable, preferably by a switching and/or controldevice. Thus, in accordance with a particularly preferred embodiment, itis possible to effect the action of the actuator element on the drivefluid only upon reaching or exceeding a predetermined rotational speedvalue or a predetermined value of the electrical energy generated by theelectrodynamic converter (which is then at least partly used as aswitching and/or control signal).

The electrodynamic converter, in the following also called thegenerator, preferably has a stator and a rotor, wherein the rotor isconnected to the rotary part or is implemented as a part of the rotarypart. The rotary part, for example, comprises the rotor of the handleacted upon by the drive fluid, a shaft rotationally mounted in thehandle, for example a hollow shaft for the releasable support of thetreatment tool, or the shaft of a tool that can be held in the handle.The rotor preferably comprises a magnetic element and the stator atleast a coil, but of course the reverse arrangement is also possible.The magnetic element is preferably provided on the rotary part, so thatthe magnetic element can be set into motion by the rotary part.Preferably, the magnetic element is designed as a permanent magnet,particularly as a disc magnet, that is fastened to the rotary part.Alternatively, the rotary part can itself be magnetic, for example dueto being manufactured of a magnetic material or by being magnetised.

The control or regulation circuit limits, controls or regulates therotational speed of the rotary part and the tool that can be connectedto it to a maximum or set value, in particular under low load or idlingof the handle, in order to reduce the noise emission of the handle andto reduce the mechanical stress on the ball bearings located in thehandle that support the rotary part. Rotational speed limiting alsopermits gentler application of the tool to the point of treatment. Inaccordance with one embodiment, the control or regulation circuit isdesigned to limit the rotational speed of the rotary part and of thetool to a value in a range from about 300,000-150,000 rpm, preferably toa value in the range from about 275,000-200,000 rpm, and particularlypreferably to about 250,000 rpm.

In accordance with one embodiment, the at least one coil is wound arounda soft magnetic coil core that concentrates the magnetic flux of themagnetic element of the generator and guides it to the coil. Inparticular, the soft magnetic coil core that comprises one or morelayers, preferably electrically isolated from one another, isring-shaped and surrounds the outer circumference of the magneticelement. This simplifies their installation in the handle, particularlywhen the electrodynamic converter comprises multiple coils.

In accordance with another embodiment, the at least one actuator elementis implemented as an actuator element, particularly a mechanical onethat can be driven by electrical energy, for example a valve,particularly a control valve or a proportional valve, particularlypreferably as a solenoid valve or a throttle. The valve or the throttleare preferably located directly on or in the line for the drive fluid toor from the rotary part or directly on or in the fluid branch line.

According to another embodiment, the fluid branch line connects thefluid line carrying the drive fluid to the rotary part and the fluidline carrying the drive fluid from the rotary part. Alternatively, thefluid branch line can diverge from the fluid line carrying the drivefluid to the rotary part and open into a hollow chamber of a hollowouter shell of the handle. Both alternatives thus have the advantagethat they permit a portion of the drive fluid unnecessary for drivingthe rotary part to be drained through the fluid branch line.

To achieve even operation of the rotary part, according to oneembodiment the fluid line carrying the drive fluid to or from the rotarypart has an auxiliary line that bypasses the actuator element, so thatat least a part of the drive fluid can bypass the actuator element. Thesupply of the rotary part with drive fluid is thus composed of acontinuously flowing or constant drive fluid stream and a variable drivefluid stream that can be changed by the action of the actuator element.

According to one embodiment, the control or regulation circuit has aswitching and/or control device designed for the selective supply of theat least one actuator element with electric energy generated by theelectrodynamic converter, depending on the rotational speed of therotary part. As already explained earlier, this makes it possible tomake the action of the actuator element on the drive fluid depend on therotational speed of the rotary part, or to control the action of theactuator element on the drive fluid depending on the rotational speed ofthe rotary part. The electrical energy generated by the electrodynamicconverter (due to the direct relationship between the rotational speedof the rotary part and the electrical energy generated) is preferably atleast partly also used as a switching and/or control signal. Theswitching and/or control device preferably permits the supply of theactuator element with electrical energy generated by the electrodynamicconverter or action of the actuator element on the drive fluid only ifthe rotational speed of the rotary part has achieved or exceeded apredetermined value, for example about 200,000 rpm or about 250,000 rpmor about 275,000 rpm.

According to a preferred embodiment, the switching and/or control devicehas a device for determining the rotational speed of the rotary part.The device for determining the rotational speed of the rotary part canbe implemented by components that, for example, use directly orindirectly the electrical energy generated by the electrodynamicconverter or a value of the electrical energy generated by theelectrodynamic converter for the determination of the rotational speedof the rotary part. Such components can particularly be implementedusing a microcontroller or by a radiation source and a semiconductorelement receiving a radiation, as will be explained in more detailbelow.

Alternatively, the device for determining the rotational speed of therotary part can have components that do not derive the rotational speedof the rotary part from the electrical energy generated by theelectrodynamic converter. Such components can for example be implementedby a sensor for the detection of pressure variations in the drive fluid,in particular by a microphone that detects the sound that is emitted bythe rotary part and that changes depending on the rotational speed orchanges in the rate of flow velocity of the drive fluid, or by anoptical detection device, which for example detects radiation emitted orreflected by the rotary part or conducted by or through the rotary part.

According to a particularly preferred embodiment, the switching and/orcontrol device comprises a microcontroller that is electricallyconnected to the electrodynamic converter and that is designed tocompare a value of the electrical energy generated by the electrodynamicconverter, particularly the voltage, with a predetermined limit valueand to permit the supply of the actuator element with the electricalenergy generated by the electrodynamic converter, if the value of theelectrical energy generated by the electrodynamic converter reaches orexceeds the predetermined value.

According to an alternative embodiment, the switching and/or controldevice comprises a radiation source and a radiation receiving sensor,particularly a semiconductor element, for example a photodiode, whereinthe radiation source can be supplied with electrical energy from theelectrodynamic converter and the radiation receiving sensor is locatedin such a way that it receives radiation emitted from the radiationsource, so that an electric circuit can be closed between theelectrodynamic converter and the actuator element and the actuatorelement can be supplied with electrical energy generated by theelectrodynamic converter when the sensor detects that the radiationsource is emitting radiation or emitting radiation that exceeds apredetermined limit value. The radiation source is particularly designedin such a way that it only emits radiation when the electrical energygenerated by the generator that is directed at the radiation sourceexceeds a threshold value. The radiation source is for example designedas a light-emitting diode.

According to a preferred embodiment, the electrodynamic converter iscomprised of multiple coils, wherein at least a first coil isexclusively provided for the supply of the actuator element withelectrical energy, particularly for carrying out the actuation process,and wherein at least a second coil is exclusively provided for thesupply of the switching and/or control device with electrical energy,particularly for the generation of a switching and/or control signal forthe actuator element. In this manner, in particular when multiple firstcoils are exclusively provided for the supply of the actuator elementwith electrical energy, a reliable and sufficient energy supply to theactuator element is ensured.

In order to achieve reliable function of the actuator element andpreferably also of the switching and/or control device, according to oneembodiment the control or regulation circuit has a device for therectification of the electrical energy generated by the electrodynamicconverter, so that the actuator element and preferably also theswitching and/or control device can be supplied with direct current.

According to a preferred embodiment, the entire control or regulationcircuit is housed in the handle and/or in a connecting part that can beconnected to the handle, in particular in an adapter or in a couplingelement. At least the actuator element, and preferably also theswitching and/or control device, is independent of an electrical energysource located outside the handle and/or the connecting part. Thus, inan advantageous manner, the control or regulation circuit is fullyfunctional when the handle is connected to a purely pneumatic supplyunit.

A method for limiting, controlling or regulating the rotational speed ofa medical or dental, fluid-driven handle having a rotary part that canbe set in rotary motion by a drive fluid to drive a tool connected tothe rotary part, the fluid line carrying the drive fluid to or from therotary part or in a fluid branch line that is connected to the fluidline and a control or regulation circuit that is designed to limit, tocontrol or to regulate the rotational speed of the rotary part, whereinthe control or regulation circuit comprises an electrodynamic converterdriven by the rotary part and at least one actuator element that isconfigured to act on the drive fluid flowing in the fluid line or thefluid branch line, wherein the at least one actuator element iselectrically connected to the electrodynamic converter, wherein themethod comprises driving the rotary part with the drive fluid,generating electrical energy with electrodynamic converter, supplyingelectrical energy from the electrodynamic converter to the at least oneactuator element, and acting on the drive fluid flowing in the fluidline or the fluid branch line in an actuation process with the actuatorelement to the limit, control or regulate the rotational speed.

These and other embodiments will be described below with reference tothe following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an external view of a medical or dental, fluid-drivenhandle with a control or regulation circuit for the limiting, control orregulation of the rotational speed to a maximum or predeterminedrotational speed value.

FIGS. 2 through 8 show cross sectional views of different embodiments ofmedical or dental, fluid-driven handpieces, with a control or regulationcircuit for the limiting, control or regulation of the rotational speedto a maximum or predetermined rotational speed value, that have anactuator element that is supplied with electrical energy from anelectrodynamic converter.

FIG. 9 shows a medical or dental treatment device with a control and/orregulation device for the control and/or regulation of the rotationalspeed of the rotary part.

FIGS. 10 and 11 show cross sectional views through medical or dental,fluid-driven handpieces for use with a medical or dental treatmentdevice in FIG. 9.

DETAILED DESCRIPTION

The medical or dental, fluid-driven handle 1 shown in FIG. 1 is designedas an elongated, pipe-shaped instrument that on one end has a connection18 to one or more media sources, for example to a fluid source,particularly to a compressed air source. The handle 1 as shown in FIG. 1comprises two parts, namely a handpiece 2 and a connecting part 3 thatcan connect to the handpiece 2 and that is designed for example as acoupling or adapter. The connecting part 3 and the handpiece 2 can bereleasably connected together using a coupling device 19. The connection18 provided on the supply end of the connecting part 3, as shown in FIG.1, comprises multiple connection pieces 20, which connect lines orchannels provided in the connecting part 3 with one or more mediasources, particularly with a compressed air source, preferably also witha source for liquids. The lines or channels extend through theconnecting part 3 and, preferably through the coupling device 19, carrythe medium or media to the handpiece 2. Alternatively it is of coursealso possible that the handle 1 only comprises the handpiece 2 and thaton the supply end of the handpiece 2 a connection similar or identicalto connection 18 to one or more media sources is provided.

A control or regulation circuit 8 that is described below in more detailfor the limiting, control or regulation of the rotational speed of arotary part 4 to a rotational speed value is housed, preferablycompletely, in handle 1. According to different embodiments, the controlor regulation circuit 8 is either completely housed in handpiece 2 or atleast parts of the control or regulation circuit 8, particularly anactuator element 10, preferably a valve 10A, are located in theconnecting part 3.

The handpiece 2 comprises a handle part 21 that is curved or has twosegments arranged at an angle to one another, and an adjacent head part2. On head part 22 there is provided a tool opening 23 (see FIG. 2)through which a tool can be releasably inserted into the head part 22.The tool opening 23 is arranged laterally on the head part 22, so thatthe tool projects out of the head part 22 at an angle to the handle part21 or its longitudinal axis. On the end of the head part 22 opposite thetool opening 23 there is a push-button 24 provided that is operativelyconnected to a tool release device located in the head part 22 in orderto release the tool from the head part 22. Of course, the handle 1 orthe handpiece 2 can also have other known forms, for example a pistolshape or a straight-shaped implementation.

As can be seen in FIG. 2, a fluid line 5 carrying the drive fluidtowards the head part 22 or to a rotary part 4 located in head part 22and a fluid line 6 carrying the drive fluid away from the head part 22or from the rotary part 4 located in the head part 22 extend through thehandpiece 2, particularly through the handle part 21. Other media lines,for example one or more media lines for cooling media, optical lightguides or electrical lines, may also extend through the handpiece 2. Thefluid line 5 carries the drive fluid, for example compressed air orwater, to a drive unit 25 that comprises at least a rotary part 4 thatcan be set in rotary motion, for example an impeller, a rotor of an airor turbine motor, a shaft, a chucking device for the tool, etc.

According to the embodiment of the handpiece 2 shown in FIG. 2, therotary part 4 comprises a rotor 26 and a hollow shaft 27 to which therotor 26 is fastened and in which is located a chucking device for thetool or which is part of the chucking device. The rotary part 4 and thetool that can be connected to it are supported by two roller bearings28, 29 in a rotary fashion in the handpiece 2. The roller bearings 28,29 are supported on rotationally fixed components of the handpiece 2,for example the outer shell 30 (see FIG. 1).

In the head part 22 of the handpiece 2 there is provided anelectrodynamic converter or generator 9 comprising a rotor and a stator.The stator is formed of at least one, preferably multiple, coils 11 andpreferably of a soft magnetic coil core around which the coils 11 arewound. The coils 11 and the coil core surround the rotor which has amagnetic element 12, or are located near the rotor. As shown in FIG. 2,the rotor comprises a magnetic element 12 connected to the rotary part 4which can be set into rotational motion with the rotary part 4, inparticular a disc-shaped magnetic element with a hole through which thehollow shaft 27 extends. Instead of a separate magnetic element it isalso possible to implement the rotary part 4 or a part thereofmagnetically, for example by magnetising it. Preferably the rotor 26 isat least partly magnetic, in particular the blades of the rotor 26 aremagnetic.

The fluid line 5 ends near the rotary part 4 or the rotor 26, andintroduces the drive fluid to rotary part 4, particularly the rotor 26,or into a hollow chamber in the head part 22 in which the rotary part 4or the rotor 26 are supported. By subjecting the rotor 26 to the drivefluid from the fluid line 5, the rotor 26 is set in rotary motion andthus the electrodynamic converter 9 is also activated and a voltage isinduced in the coils 11. The magnitude of the voltage induced in thecoils 11 thereby correlates with the rotational speed of the rotor, therotary part 4 and the tool.

The generator 9 is a part of the control or regulation circuit 8 for thelimiting, control or regulation of the rotational speed of the rotarypart 4 and/or of a tool connected to the rotary part 4. According to theembodiment shown in FIG. 2, the control or regulation circuit 8comprises not only the generator 9 but also an actuator element 10 thatcan be driven by electrical energy, a switching and/or control device 14and electric lines 31, 31A that connect the generator 9 to the switchingand/or control device 14 and the actuator element 10. The actuatorelement 10, implemented as a valve, particularly as a control valve or aproportional valve, acts on the drive fluid flowing in the fluid line 5by means of an actuation process. For example, the actuator element 10changes the fluid pressure or the volume flow of the drive fluid,particularly by changing the inner diameter of the fluid line 5 that thedrive fluid can flow through, so that the rotational speed of the rotarypart 4 can be changed.

The actuator element 10 receives electrical energy generated bygenerator 9 through the electric lines 31, 31A to carry out theactuation process. A part of the energy imparted to the rotary part 4 bythe drive fluid is thus used for operation of the actuator element 10.If the rotational speed of the rotary part 4 is too high, then theactuator element 10 reduces the energy introduced to the rotary part 4,for example by reducing the fluid pressure or the volume flow of thedrive fluid, whereby the rotational speed of the rotary part 4 falls. Ifthe rotational speed of the rotary part 4 is too low, then the actuatorelement 10 increases the energy introduced to the rotary part 4, forexample by increasing the fluid pressure or the volume flow of the drivefluid, so that the rotational speed of the rotary part 4 rises.

According to a simple embodiment not shown, the control or regulationcircuit 8 comprises the generator 9 that can be driven by the rotarypart 4, the actuator element 10, the electric lines 31, 31A to connectthe generator 9 to the actuator element 10, and a part of the fluid line5. Preferably, however, the control or regulation circuit 8 additionallycontains a switching and/or control device 14 which supplies theactuator element 10 selectively with electrical energy generated by thegenerator 9, in particular depending on the rotational speed of therotary part 4, and which particularly has a device 32 for determinationof the rotational speed of the rotary part 4, as shown in FIG. 2. Theswitching and/or control device 14 shown in FIG. 2 is implemented as amicrocomputer or a microcontroller 15 and connected electrically betweenthe generator 9 and the actuator element 10.

The microcontroller 15 receives electrical energy generated by thegenerator 9 through the lines 31A and measures or determines a currentparameter or value of the electrical energy, which correlates with therotational speed of the rotary part 4, for example the voltage or thecurrent. The microcontroller 15 or at least parts of the microcontroller15 thus determine the rotational speed of the rotary part 4 and form thedevice 32 for determining the rotational speed of the rotary part 4. Inmicrocontroller 15, furthermore, there is at least one limit valuestored for the current parameter of the electrical energy, so that themicrocontroller 15 can compare the current parameter with the limitvalue and selectively supply the actuator element 10 with electricalenergy generated by the generator 9 depending on the relationship of thecurrent parameter with the limit value. For example, the switchingand/or control device 14 supplies the actuator element 10 withelectrical energy or closes the circuit between the generator 9 and theactuator element 10 when the rotational speed of the rotary part 4 andthus the current parameter of the electrical energy generated by thegenerator 9 reaches or exceeds the limit value. Alternatively, theswitching and/or control device 14 interrupts the supply of the actuatorelement 10 with electrical energy or opens the circuit between thegenerator 9 and the actuator element 10 when the rotational speed of therotary part 4 and thus the current parameter of the electrical energygenerated by the generator 9 reaches or falls below the limit value.Particularly preferably, the actuator element 10 that can be driven byelectrical energy is implemented as a proportional valve, whereby theswitching and/or control device 14 supplies the proportional valve withelectrical energy in such a way that it carries out a continualactuation process depending on the rotational speed of the rotary part4.

The other embodiments shown in FIGS. 3-8 of handpieces with a control orregulation circuit 8 for limiting, control or regulation of therotational speed of the rotary part are similar in many regards to thestructure and function of the handpiece 2 in FIG. 2. For this reason,particularly those features will be described below that differentiatethe handpieces of FIGS. 3-8 from the handpiece 2 of FIG. 2.

The control or regulation circuit 8 of handpiece 2 in FIG. 3 differs byan alternative design of the switching and/or control device 14 and/orby an alternative design of the device 32 for determining the rotationalspeed of the rotary part 4: Device 32 comprises a radiation source 16,for example one or more light-emitting diodes, and a radiation receivingsensor 17, for example a photodiode. The radiation source 16 can besupplied with electrical energy by the electrodynamic converter 9through the electric lines 33. If the electrical energy generated by thegenerator 9 reaches or exceeds a predetermined value, for example theswitching voltage or passing voltage of the light-emitting diode, thenradiation source 16 emits electromagnetic radiation. Theradiation-receiving sensor 17 is located and designed in such a way thatit receives this radiation emitted by the radiation source 16. If thesensor 17 detects that the radiation source 16 emits radiation or emitsradiation that exceeds a predetermined limit value, then theradiation-receiving sensor 17 and/or the switching and/or control device14 close the circuit between the generator 9 and the actuator element10, so that the actuator element 10 can be supplied with the electricalenergy generated by the generator 9. If the radiation source 16 does notemit radiation or if the radiation source 16 emits radiation that fallsbelow a predetermined limit value, the radiation-receiving semiconductorelement 17 and/or the switching and/or control device 14 open thecircuit between the generator 9 and the actuator element 10, so that theactuator element 10 is no longer supplied with the electrical energygenerated by the generator 9. The switching and/or control device 14preferably also has a microcontroller 15 that processes the signals fromthe sensor 17 and carries out the closing of the circuit. The actuatorelement 10, the sensor 17 and/or the switching and/or control device 14are supplied with the electrical energy generated by the generator 9 viathe electric lines 31A.

The devices 32 in FIGS. 2 and 3 each thus use (directly or indirectly)the electrical energy generated by the generator 9 or a value thereoffor determining the rotational speed. Alternatively, FIG. 8 shows adevice 32′ for determining the rotational speed of the rotary part 4which does not derive the rotational speed of the rotary part 4 from theelectrical energy generated by the electrodynamic converter 9. Thedevice 32′ comprises a sensor for the detection of pressure variationsin the drive fluid, for example a microphone 34, which detects the soundemitted by the rotary part 4 that changes depending on the rotationalspeed, or changes of the flow velocity of the drive fluid in the fluidlines 5 or 6. The switching and/or control device 14, which preferablyalso has a microcontroller 15, processes the signals from the device32′, i.e. from the microphone 34, and closes or opens or causes theclosure or opening of the circuit between the generator 9 and theactuator element 10 depending on the rotational speed of the rotary part4/the signals from the device 32′. The electrical energy generated bythe generator 9, according to this embodiment, thus serves as theelectrical supply for the actuator element 10, the switching and/orcontrol device 14, and the device 32′ (via the electric lines 33), butnot for determining the rotational speed of the rotary part 4.

The device 32′ for determining the rotational speed of the rotary part4, which does not derive the rotational speed of the rotary part 4 fromthe electrical energy generated by the electrodynamic converter 9, canalternatively also be implemented with other components, for example byan optical detection device that detects radiation emitted or reflectedby the rotary part 4 or conducted by or through the rotary part 4.

The handpiece 2 shown in FIG. 4 comprises a fluid line 5 for carryingthe drive fluid to the rotary part 4 and an auxiliary line 5A of thefluid line 5 which bypasses the actuator element 10 provided in thefluid line 5. The auxiliary line 5A originates from the fluid line 5before the actuator element 10 relative to the direction of flow of thedrive fluid, and opens back into the fluid line 5 after the actuatorelement 10. Alternatively, it is also possible that auxiliary line 5Aremains separate from the fluid line 5 up to the rotary part 4. At leasta part of the drive fluid can thus be routed around the actuator element10, permitting a calmer, more even drive of the rotary part 4. Ofcourse, it is also possible to place the actuator element 10 in theauxiliary line 5A.

In the embodiment of the handpiece 2 shown in FIG. 5, the actuatorelement 10, which is again preferably implemented as a valve, is locatedin the fluid line 6 for carrying the drive fluid away from the rotarypart 4 or head part 22.

The handpieces 2 shown in FIGS. 6 and 7 each have a fluid branch line 7that connects or short circuits the fluid line 5 carrying the drivefluid to the rotary part 4 and the fluid line 6 carrying the drive fluidfrom the rotary part 4. The actuator element 10, which is preferablyimplemented as a valve, is located in or on the fluid branch line 7. Ifthe actuator element 10 is not completely closed, a part of the drivefluid flows directly from the fluid line 5 into fluid line 6. In thehandpiece 2 shown in FIG. 6, the fluid branch line 7 opens into asegment 6A of fluid line 6 implemented as a pipe, or it is connected tothe same.

In the handpiece 2 in FIG. 7, the fluid line 6 carrying the drive fluidfrom the rotary part 4 comprises only a short pipe-like segment 6B andis subsequently implemented by the outer shell 30 of the handpiece 2.The used drive fluid or the drive fluid flowing away from rotary part 4thus flows through the hollow chamber 13 into the outer shell 30. Thefluid branch line 7 in this embodiment also opens into the hollowchamber 13.

In the embodiments shown in FIGS. 2-8 the electrodynamic converter 9supplies all components of the control or regulation circuit 8 withelectrical energy, in particular the actuator element 10, the switchingand/or control device 14 and the device 32 for determining therotational speed of the rotary part 4. The control or regulation circuit8 or the handle 1 thus require no electrical contact or lines connectinghandle 1 with an external energy source, that is, one located outsidehandle 1.

In contrast, the treatment device 40 and handles 1′ shown in FIGS. 9-11are designed in such a way that at least according to certainembodiments their control or regulation circuit can be at least partlyoperated by electrical energy which does not originate from theelectrical energy source represented by the generator 9, in particularfrom an electrical energy source outside the handle 1′. The treatmentdevice 40 and handles 1′ in FIGS. 9-11 thus also have their owninventive aspect independent of the handles described above.

The medical or dental treatment device 40 comprises a handle 1′, arotary part 4 provided in the handle 1′ that can be set into rotarymotion by a drive fluid, for the driving of a tool that can be connectedto the rotary part 4, a device 42, 42A for determining the rotationalspeed of the rotary part 4 and a control and/or regulation device 41 forthe control and/or regulation of the rotational speed of the rotary part4 that is designed to compare the rotational speed of the rotary part 4determined by the device 42 for determining the rotational speed of therotary part 4 with a set value and in the case of deviation of thedetected rotational speed from the set value to operate an actuatorelement 10 that acts upon the drive fluid in order to limit therotational speed of the rotary part 4 to the set value or to cause it toapproach the set value, wherein the actuator element 10 is implementedas an actuator element 10 that is driven by electrical energy and thatis located in the handle 1′.

The great advantage of the location of the actuator element 10 in thehandle 1′ is due to the fact that the distance between the actuatorelement 10 and the rotary part 4 is very small, so that the dead time,that is, the period of time between a change in the rotational speed andthe reaction of the actuator element is also very small. Thus a stableoperation of the treatment device 40 is obtained in an advantageousmanner, in particularly without the risk of oscillation in the controlor regulation circuit. Preferably the entire control or regulationcircuit, which particularly comprises the device 42, 42A for determiningthe rotational speed of the rotary part 4, the control and/or regulationdevice 41 and the actuator element 10 can be driven with electricalenergy and electrical signals, so that the operation of the control orregulation circuit is accelerated even further or the dead time reducedeven further.

According to one embodiment, the actuator element 10 is implemented as avalve, particularly as a control valve, solenoid valve or proportionalvalve, or as a throttle.

The medical or dental treatment device 40 shown in FIG. 9 comprises ahandle 1′ that is designed substantially identically to the handle 1shown in FIG. 1. The handle 1′ comprises either only a handpiece 2′ thatis releasably connected via a coupling device 47 at least to a fluidsource 46 and possibly also at least to parts of the control and/orregulation device 41, as shown in FIG. 9, or alternatively a handpiece2′ and a releasable connecting part 3, as can be seen in FIG. 1.

According to one embodiment, the medical or dental treatment device 40furthermore comprises an energy source that provides electrical energyfor the operation of the actuator element 10, wherein the energy sourceis located either in the handle 1′ or outside the handle 1′. If theenergy source is located in the handle 1′, then it comprises for examplea battery or a rechargeable battery or an electrodynamic converter 9that can be driven by the drive fluid. The electrodynamic converter 9 orgenerator can preferably be directly or indirectly driven by the rotarypart 4, as shown in FIG. 10.

The generator 9 of the handle 1′ in FIG. 10, however, does not serveonly or primarily to provide the energy supply of the actuator element10, but is especially (due to the correlation described above betweenthe rotational speed of the rotary part 4 and the electrical energygenerated by the generator 9) a part of the device 42 for determiningthe rotational speed of the rotary part 4. The electrical energygenerated by the electrodynamic converter 9 preferably servesexclusively to determine the rotational speed of the rotary part 4. Inother words, the device 42 for determining the rotational speed of therotary part 4 thus has an electrodynamic converter 9 that can be drivenby the rotary part 4, so that the rotational speed of the rotary part 4can be derived from the electrical energy generated by theelectrodynamic converter 9. The device 42 is connected by electric lines48 with the control and/or regulation device 41 and sends either theelectrical energy generated by the generator 9 directly to the controland/or regulation device 41, or modifies the electrical energy generatedby the generator 9 by means of a component 42A. The component 42A is forexample implemented as an amplifier, rectifier, filter, analogue/digitalconverter or microcontroller. The electrical energy modified bycomponent 42A is subsequently, particularly in the form of an electricrotational speed signal, directed through the electric lines 48 to thecontrol and/or regulation device 41.

The control and/or regulation device 41 compares the electrical energyreceived from the device 42 or the rotational speed signal with arotational speed set value that is fixed or can be changed by the user,and in case of deviation of the determined rotational speed from the setvalue operates the actuator element 10 by an electrical, control orregulation signal in such a way that it acts on the drive fluid so thatthe rotational speed of the rotary part 4 approaches the rotationalspeed set value or is limited to it, as already described above.

If the electrical energy generated by the electrodynamic converter 9serves exclusively for the determination of the rotational speed of therotary part 4, then the treatment device 40 comprises a separate energysource that supplies the actuator element 10 (by means of electric linesnot shown) and possibly also the device 42 for determining therotational speed of the rotary part 4, particularly component 42A, withelectrical energy. This electrical energy source is preferably locatedoutside the handle 1′, in particular it is implemented as a part of thecontrol and/or regulation device 41, wherein if necessary the electriclines 48 can also be used for the transmission of electrical energy. Areleasable electrical connection between the actuator element 10 and theelectrical energy source is particularly preferably provided,particularly as a part of the coupling device 47, for example slidingelectrical contacts or electrical plug contacts.

Alternatively, it is also possible that the control and/or regulationdevice 41 for the control and/or regulation of the rotational speed ofthe rotary part 4 is completely located in the handle 1′, for example inthe component 42A or as a part of the component 42A. The generator 9 orthe electrical energy generated by the generator 9 preferably alsoexclusively serves to determine the rotational speed of the rotary part4, so that in this case the electric lines 48 are particularly used forthe supply of the control and/or regulation device 41, of the device 42for determining the rotational speed of the rotary part 4 and theactuator element 10 with electrical energy. Particularly preferably, theelectrical energy is provided by an energy source outside the handle 1′.

According to an alternative embodiment, the device 42 for determiningthe rotational speed of the rotary part 4 has a sensor to detectpressure variations in the drive fluid, in particular a microphone 34that detects the sound emitted by the rotary part 4 that changesdepending on the rotational speed, or changes in the rate of flow of thedrive fluid. The structure of the device 42 corresponds to the structureof the device 32 described in FIG. 8.

According to another embodiment, the device 42 for determining therotational speed of the rotary part 4 is implemented by an opticalsensor device 45, which for example detects radiation emitted,reflected, or conducted by or through the rotary part 4 (see FIG. 11).The device 42, for example, comprises a radiation source 49,particularly a light-emitting diode, which emits radiation towards therotary part 4. A reflector 50 is provided on the rotary part, forexample a reflecting metal strip, which reflects at least a part of theradiation to a radiation sensor 51, for example an opticalsemiconductor, particularly a photodiode. By means of the radiationreflected from the reflector 50 and detected by the sensor 51, thesensor 51 is excited to emit a sensor signal that corresponds to therotational speed. As described with reference to FIG. 9, the component42A can again be optionally provided that modifies the sensor signal.The sensor signal is forwarded to the control and/or regulation device41, which determines the rotational speed based on the sensor signal,compares it to a rotational speed set value, and in case of deviation ofthe determined rotational speed from the set value uses a, particularlyelectrical, control and/or regulation signal to operate the actuatorelement 10.

The supply of electrical energy to the actuator element 10, the device42 for determining the rotational speed of the rotary part 4 andoptionally the component 42A which preferably comprises the controland/or regulation device 41 is carried out by an electrical energysource, preferably located outside the handle 1′, via the electric lines48.

According to one embodiment, the control and/or regulation device 41 forthe control and/or regulation of the rotational speed of the rotary part4 is located at least partly outside the handle 1′.

In FIGS. 10 and 11 the actuator element 10 is disposed in or on thefluid line 5 carrying the drive fluid from the fluid source 46 to therotary part 4. Of course, it is also possible for actuator element 10 tobe located on fluid line 6 returning the drive fluid from the rotarypart 4 or on a fluid branch line that connects the fluid lines 5, 6 (seeFIGS. 5 and 6).

In FIGS. 10 and 11 actuator element 10 is located in the handpiece 2′.Clearly, it is also possible to place the actuator element 10 in theconnecting part 3 of the handle 1′.

The invention is not limited to the embodiments represented here butinstead comprises all embodiments that employ or include the basicappropriate functional principle of the invention. In addition, allfeatures of all the embodiments described and illustrated here may becombined with one another.

What is claimed is:
 1. A medical or dental, fluid-driven handle,comprising a rotary part that can be set in rotary motion by a drivefluid, to drive a tool that can be connected to the rotary part, a fluidline carrying the drive fluid to or from the rotary part or a fluidbranch line that is connected to a fluid line for carrying the drivefluid to or from the rotary part, and a control or regulation circuitthat is designed to limit, control or regulate the rotational speed ofthe rotary part, wherein the control or regulation circuit comprises anelectrodynamic converter driven by the rotary part for generation ofelectrical energy and at least one actuator element that is configuredto act on the drive fluid flowing in the fluid line or the fluid branchline, wherein the at least one actuator element is electricallyconnected to the electrodynamic converter in such a way that the atleast one actuator element is supplied with electrical energy generatedby the electrodynamic converter in order to carry out an actuationprocess.
 2. The medical or dental, fluid-driven handle according toclaim 1, wherein the electrodynamic converter comprises at least a coiland a magnetic element and wherein the magnetic element is located onthe rotary part so that the magnetic element can be set in rotary motionby the rotary part.
 3. The medical or dental, fluid-driven handleaccording to claim 2, wherein the at least one coil is wound around asoft magnetic coil core.
 4. The medical or dental, fluid-driven handleaccording to claim 1, wherein the actuator element is designed as one ofa valve, a control valve, a proportional valve and a throttle.
 5. Themedical or dental, fluid-driven handle according to claim 1, wherein thefluid branch line connects the fluid line carrying the drive fluid tothe rotary part and the fluid line carrying the drive fluid from therotary part or that the fluid branch line originates from the fluid linecarrying the drive fluid to the rotary part and opens into a hollowchamber of a hollow outer shell of the handle.
 6. The medical or dental,fluid-driven handle according to claim 1, wherein the fluid linecarrying the drive fluid to or from the rotary part comprises anauxiliary line that bypasses the actuator element, so that at least apart of the drive fluid can bypass the actuator element.
 7. The medicalor dental, fluid-driven handle according to claim 1, wherein the controlor regulation circuit comprises a switching and/or control devicedesigned for the selective supply of the at least one actuator elementwith electric energy generated by the electrodynamic converter dependingon the rotational speed of the rotary part.
 8. The medical or dental,fluid-driven handle according to claim 7, wherein the control and/orregulation device comprises a device for determining the rotationalspeed of the rotary part.
 9. The medical or dental, fluid-driven handleaccording to claim 7, wherein the switching and/or control devicecomprises a microcontroller that is electrically connected to theelectrodynamic converter and is designed to compare a value of theelectrical energy generated by the electrodynamic converter with apredetermined limit value and to permit the supply of the actuatorelement with electrical energy generated by the electrodynamic converterif the value of the electrical energy generated by the electrodynamicconverter reaches or exceeds the predetermined value.
 10. The medical ordental, fluid-driven handle according to claim 7, wherein the switchingand/or control device comprises a radiation source and a radiationreceiving sensor, wherein the radiation source can be supplied withelectrical energy from the electrodynamic converter and the radiationreceiving sensor is disposed in such a way that it receives radiationemitted from the radiation source, so that a circuit can be closedbetween the electrodynamic converter and the actuator element and theactuator element can be supplied with electrical energy generated by theelectrodynamic converter when the sensor detects that the radiationsource is emitting radiation or emitting radiation that exceeds apredetermined limit value.
 11. The medical or dental, fluid-drivenhandle according to claim 1, wherein the electrodynamic convertercomprises multiple coils, wherein at least a first coil is exclusivelyprovided for the supply of the actuator element with electrical energy,and wherein at least a second coil is exclusively provided for thesupply of the switching and/or control device with electrical energyand/or for the generation of a switching and/or control signal for theactuator element.
 12. The medical or dental, fluid-driven handleaccording to claim 1, wherein the control or regulation circuitcomprises a device for the rectification of the electrical energygenerated by the electrodynamic converter, so that the actuator elementand/or the control and/or regulation device can be supplied with directcurrent.
 13. The medical or dental, fluid-driven handle according toclaim 1, wherein the entire control or regulation circuit is housed inat least one of the handle and a connecting part that can be connectedto the handle, and at least one of the actuator element and theswitching and/or control device is independent of an electrical energysource located outside the handle and/or the connecting part.
 14. Themedical or dental, fluid-driven handle according to claim 1, wherein thecontrol or regulation circuit is designed to limit, to control or toregulate the rotational speed of the rotary part and of the tool to avalue in a range from about 300,000-150,000 rpm or to a value in therange from about 275,000-200,000 rpm or to about 250,000 rpm.
 15. Amethod for limiting, controlling or regulating the rotational speed of amedical or dental, fluid-driven handle having a rotary part that can beset in rotary motion by a drive fluid to drive a tool connected to therotary part, a fluid line carrying the drive fluid to or from the rotarypart or a fluid branch line that is connected to the fluid line, and acontrol or regulation circuit that is designed to limit, to control orto regulate the rotational speed of the rotary part, wherein the controlor regulation circuit comprises an electrodynamic converter driven bythe rotary part and at least one actuator element that is configured toact on the drive fluid flowing in the fluid line or the fluid branchline, wherein the at least one actuator element is electricallyconnected to the electrodynamic converter, wherein the method comprises:driving the rotary part with the drive fluid; generating electricalenergy with the electrodynamic converter; supplying electrical energyfrom the electrodynamic converter to the at least one actuator element;and acting on the drive fluid flowing in the fluid line or the fluidbranch line in an actuation process with the actuator element to limit,control or regulate the rotational speed.